Caries is a multifactorial infectious disease, determined by the dynamic balance between pathological factors leading to demineralization and protective factors leading to remineralization (Featherstone, 2004).
Many salivary proteins have been suggested to play a role as either cariogenic or anti-cariogenic factors, depending on their ability to inhibit the growth of acid-producing bacteria, to aggregate them, to promote their adhesion to the tooth surface or to modify the mineralization/demineralization balance (Lenander-Lumikari and Loimaranta, 2000; Nieuw Amerongen et al., 2004).
Understanding the role of salivary proteins in caries development is made more complicated by the fact that many of these proteins are multifunctional (the same protein may perform different functions), redundant (many proteins seem to share the same functions) and amphifunctional (the same protein may have opposite effects, depending on the intraoral environment) (Rudney, 2000; Humphrey and Williamson, 2001).
No significant differences in the protein composition of parotid saliva (Dodds et al., 1997) and whole saliva (Banderas-Tarabay et al., 2002) were detected between caries-active (CA) and caries-free (CF) individuals.
Actually, each band of one-dimensional gel electrophoresis is often composed of different protein types, thus making it difficult to detect quantitative changes in specific proteins. The mapping of human salivary proteins by two-dimensional gel electrophoresis has revealed the presence of many spots which are still to be identified (Ghafouri et al., 2003): one of these proteins could turn out to be primarily involved in the development of caries.
However, the prior art does not contain any indication as to the possible existence of any specific salivary protein which may be used as a marker for the predisposition of an individual to developing caries or as an indicator of the presence of ongoing caries.